This invention relates in general to electrical cord assemblies and deals more particularly with an improved modular plug and cord assembly for telephonic and/or data signal transmission and a method for making such an assembly.
The cord assembly of the present invention is particularly adapted for use as a patch cord on a cross-connect panel, such as an AT&T 110 type panel. Such a cross-connect panel meets EIA/TIA Commercial Building Standards --"Category 5" requirements-and provides a convenient centralized location for networking the communications and data processing systems within a building and for interconnecting the systems with an outside telecommunication network. When problems of signal coupling (crosstalk) or intermittent contact (clicking) occur in such a cross-connect panel system these problems can usually be attributed to the patch cords used with the system.
A typical patch cord for a modern cross-connect panel system of the aforedescribed general type includes a flexible stranded wire cord with a patch plug attached to each end. The patch plug generally has a housing containing an inline array of flat contact blades adapted to be simultaneously pressed or plugged into and extracted from an equal number of mating insulation displacement contacts (IDCs) mounted on and projecting from the cross-connect panel. Typically the contact blades within the plug housing are connected to individual stranded wire conductors in the patch cord by IDC terminations.
While stranded wire patch cords afford the advantages of flexibility, for ease of cable buildup during panel board installation, and enhance high frequency transmission performance, due to increased pair twisting capability, these advantages do not adequately compensate for the basic incompatibility of IDC technology and stranded wire. Further, the initial concept of mass termination to enhance efficiency by cross-connecting an entire network (four pair), as opposed to terminating individual conductors, is seriously flawed by insertion of eight relatively large flat formed blade contacts at each end of the patch cord into associated IDC slots on a cross-connect panel.
U.S. Pat. No. 5,226,835 to Baker III, et al entitled Patch Plug For Cross-Connect Equipment, issued Jul. 13, 1993 and assigned to AT&T Bell Laboratories, Murray Hill, New Jersey, addresses the problem of near-end crosstalk associated with a patch plug of the aforedescribed type. The patch plug disclosed in the patent to Baker III et al includes a housing containing pairs of non-insulated flat blade contacts that cross-over and are spaced-apart from each other. The cross-over contacts add a controlled half-twist to each input wire pair for reduced crosstalk between conductor pairs within a patch plug and between adjacent patch plugs. However, the wire pairs are terminated at the flat blade contacts within the plug housing by conventional IDCs on the contacts. The further problems of IDC termination at the contacts and flat blade plugging at the cross-connect panel are not addressed by Baker III, et al.
It is the general aim of the present invention to provide an improved cord assembly which satisfies the requirements of Category 5 and which may be produced at a substantially lower cost than presently available cord assemblies. It is a further aim of the invention to provide an improved patch cord which wholly eliminates the requirements for contacts.